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T. F. GLENN. ARTIFICIAL TOOTH. APPLICATION FILED AuG.3I. IsIa.

fIzII'ImIIII Aug. J2e IMI,

EIGL

ARTIFICIAL TQQ@ l.

ricarica Specification of Letters Pa tent.

Patented lling. il'ilt.,

-Alpplication led August Si, 7.915. Serial No. @1158.

i lowing is a specification, reference being had to theaccon'ipanyingdrawings.

`My invention relates particularly to that class or' .artilicial teethwhich are commonly designated as interchangeable taeings, and

is directed especially to the means for detachably connecting theporcelain tooth body, comprising the facing, to a bridgepiece, plate, orother suitable mounting. 1 The principal objects of my invention are, toprovide. a tooth facing which may be readily removed and replaced, andfirmly lenfraged With respect to its mounting` 'by sliably connectingsaid facing with the mounting, from the gingival end of the mounting;and to provide said mounting and facing' with interlocking means so disAposed as to enable the facing to pass the root abutment or gum.

Other objects of my invention are, to provide a mounting with biteprotecting portion which will not, interfere With the engagement anddisengagement of the facing.

My invention coinprehends a tooth facing having an undercut recessextending gingivally outward in oblique relation to the lingual face ofsaid facing, and arranged to be engaged with a backing having acorrespendingprojection adapted to enter said recess, serving as a guideand arranged to support said facingin rigid relation withY saidbacking',

My invention also includes all of the various novel features of'construction and arrangement hereinafter more delinitcly specified.

lntlie accompanying drawings, Figure 1 is a central longitudinalsectional View of a. tooth racing and its backing conveniently embodyingmy invention, a portion of the backing being shown in elevation forconvenience of illustration, and the facing being` shown in dot and dashlines in an alternate position; Fig. 2 is a. central longitudinalsectional view similar to Fig. l, but showing the backing' without theridgelap 'Wall1 the facing-being shown in, dot and dash lines in anotherposition; and lig. is

a transverse horizontal sectional vievv oit' the tooth and backing shownin Figs. l and 9;, taken on the line 3---3 in cach oi said ngures.

ln said Ytigl'iiies, the tooth body 5, which is preferably composed ofporcelain, has its lingual race Atorn'ied of relatively angularsurfaces, con'iprising the iride-lap7 bite7 Y, and intervening lingualsurface termed 'the shut f), said ridge-lap and bite being disposed inlabially oblique elation with respect to the shut surface S). lhe bodyof the tooth facing 5 is provided in lingual face with a recess whichmay be in the form or' an undercut slot or groove l0, extendinglongitudinally of the facing and comprising a broad, flat cavity l2,having the edges 13 and le oif the surfaces l5 and l@ of its lingualwall disposed in a plane which extends obliquely outward With respect tothe lingual face oi said tooth and tends tou-'ard its gingival end.

The lingual t'ace or the tooth facing above described is arranged to beclothed by the backing comprising the relatively `angular Walls 20, 2land 22, respectively overlying the ridge-lap, the bite and the shutsurfaces ot' the lingual face of the tooth facing body 5. Said backingis provided with an anchor bracket or tongue 23, which is .arranged tosnugly lit the cavity 1:2 in the tooth facing or body 5, being connectedwith the hacking; Wall by the relatively narrow web 25, which ispreieral'ily arranged to accurately lit the-slot or groove l() in thetooti facing body4 The lingual surfaces of the tongue 23 are disposed inoblique relation to the shut wall Q2 of the backing, in the same generaldirection as the ridge-lap, that the tooth facing 5 may be engaged withsaid backing by a rectilinear movement from the gingival end oi. thcbacking,l incisively, from the position shown in dot and dashplines, tothe position shown in full lines, wherein the opposing surfaces ot thetooth facing and its backing absolutely conform to each other and snuglylit-together.

lt may in some cases be convenient to ,dispense with 'the backing wallQ0, as shown in Fig. Q5 for instai'ice, Where the facing 5 is en'iployedas an intermediate tooth in bridge- Work, in Which inst-ance theridge-lap7 G ot the tooth facing body 5 may abut 'directly against the,gums of the patient.

loo

t may be convenient in some instances Where the gums of the patientconsiderably overhang, to rock the tooth facing 5 into position, asshown in Fig. 2, in which instance the labial Wall of the cavity l2 maybe cut away, as shown at 27, so as to afford a greater range of movementof the tooth facing 5 with respect to the backing, and therebyfacilitate its engagement therewith, as will oe obvious from aninspection of said figure.

I am aware that various forms of tooth facings have been devised whereinattempts have been made to so form the facing` and backing as to providea rigid engagement of said facing with said backing, and to provide forprotecting the incisive edge of the facing with an inclined biteprojecting plate or wall, but, so far as I am aware, no such toothstructure has been devised that may be engaged with the backing by amovement of the facing from the gingival end obliquely With respect tothe surface adjoining the bite surface, and wherein the intei-lockingmeans serves as a guide and cli-- rects the relative movement of thetooth facing 5 with respect to the backing, in the same generaldirection as the plane of the ridge-lap.

It may be noted that although have shown and described the cavity l2 asbroad and flat, it may be of other shapes, and therefore I do not desireto limit my invention to the precise details of construction andarrangement as herein set forth, as various modifications 'may be madetherein without departing from the essential fea-tures of my inventionas defined by the appended claims.

Having thus described my invention, l claim:

l. A tooth having its lingual face formed of relatively obliquesurfaces, comprising the ridge-lap, shut and bite, and having anundercut recess, the edges of Whose lingual Wall are disposed in obliquerelation to the shut surface and extend in the same general direction asthe ridge-lap.

,2. vIn a tooth, the combination with a facing having its lingual faceformed of relatively angular surfaces, including a bite surface, and anundercut recess in said lingual face having the edges of its lingualwall disposed in a plane oblique to the surface adjoining said bitesurface and extending labially toward the gingival end, of a backing forsaid tooth having relatively angularjvalls conforming to the lingualface of said tooth, and having a tongue projecting into said recess andextending in the same ,oblique relation to the backing Wall as saidrecess' isto the lingual face of the facing. i

3'. A backing having relatively angular walls arranged to engage thelingual face of a tooth facing, and having a laterally undercut tonguewhich is arranged to engage a suitable anchor recess in said toothfacing, and which projects obliquely from said backing and in adirection tending labially toward the gingival end.

In witness whereof, I have hereunto set my hand this th day of August,A. D.,

THOMAS F. GLENN. Witnesses: ROBINSON L. VAILL, RICHARD H. MENS.

